Let √−8−6i=x+iy=z
⇒−8−6i=(x+iy)2
∴x2−y2=−8 ...(i)2xy=−6 ...(ii)
Now x2+y2=√64+36=±10 ...(iii)
From (i) and (ii),we have x=±1 and y=±3
Hence z=±(1−3i)
√−8−6i=